Digital logic circuits are sometimes arranged such that a first logic circuit operates with one supply voltage, e.g., 3.3 volts, while another circuit supplying input logic signals to the first logic circuit operates with a different supply voltage, e.g., 1.8 volts. In such a case, the logic signals supplied to the first logic circuit are incompatible with the switching threshold of the first logic circuit, which is set for applied input signals of 3.3 volts, causing erroneous and undesired switching operations.
A simple way of adjusting a switching threshold of a logic circuit to handle input logic signals of different voltage levels is needed.